W3C

Timed Text Working Group Teleconference

27 Apr 2017

See also: IRC log

Attendees

Present
Glenn, Nigel, Mike, Andreas, Thierry, Pierre, David_Ronca
Regrets
Chair
Nigel
Scribe
nigel

Contents


<scribe> scribe: nigel

This Meeting

Nigel: Today we have TPAC, IMSC, TTML, HDR in PNG.

David_Ronca: [requests TTML2 at the head of the meeting for scheduling reasons]

Nigel: Anything else for the agenda, or AOB?

group: [no AOB]

TTML

Nigel: First let's look at progress tracking.
... First thank you Glenn for assigning yourself to issues. The number you're assigned to is
... quite a bit larger than the number of branches you have open. What's happening there?

Glenn: I've either begun work on them or thought about them and have a plan. If someone
... wants to work on one and I don't have a branch for it then coordinate with me and let
... me know. We can have more than one assignee for any issue.

Nigel: That's true we can.

David_Ronca: For those issues you have begun working on but do not have a branch for it
... yet is there any reason why you wouldn't unassign yourself so people can filter on
... assignee?

Glenn: If someone wants to take one on then just coordinate with me.

Nigel: If you're assigned to issues then that will likely put
... other people off, and the flip side of that is that the Group will expect some short term work on it.

Glenn: There are 5-10 issues with no assignee that I'm less interested in, so people should
... start with that first.

David_Ronca: What I'm interested in most is not who resolves an issue but when they are
... resolved. I see 9 issues unassigned and marked as milestone TTML2WR, and 48 assigned
... to Glenn. Glenn, for the issues that are open and assigned, is there any way to put an
... expected close date on them?

Glenn: I haven't looked at them with that level of granularity.

Nigel: I think the important thing is that we have pull requests open for all those issues,
... as the first step towards issue closure.
... We talked about doing this by the end of May for all issues for the WR - I've had feedback
... this week that before concluding on the WR we should review all open issues so that we
... do not defer without due consideration, which is reasonable I think.

Glenn: Some pull requests cover multiple issues.

Nigel: Please could you mention all the issues in the Pull Request description so we can track those?

Glenn: I can add links but it may be difficult to uncover the information.

Nigel: Has anyone else assigned themselves any issues?

Pierre: My plan is to assign myself all the horizontal review comment issues and to resolve
... them before wide review. That can either be by pull request or to defer until never or later.

Nigel: Okay, will you pick them up one at a time?

Pierre: Yes, I'll review them, hopefully with Richard, and maybe close some of them in parallel
... or some sequentially. I don't plan to assign myself to them all at once.

David_Ronca: Due to other commitments I haven't managed to meet internally, but in the
... next week we'll all be back and will review and see what we can assign internally to the team.

Pierre: I have a question re:

Add an illustration of pinyin for ruby align

Pierre: There, Glenn has a comment, so you have an opinion and have thought about it, but
... you have not assigned it to yourself. Is it okay for me to proceed?

Glenn: Yes, please do. I did not try to assign to myself any of the i18n comments from the
... recent review, because they're not on the WR milestone.

Pierre: Why is that?

Glenn: Because they came in from outside the group so I consider it part of the preliminary
... wide review comments.
... If I had no other issues to work on I would probably take these on.

Pierre: There are other issues that other people can handle that don't relate to complex
... script layout issues.

Glenn: Some of those others are in areas that I do have deep expertise on.

David_Ronca: This is also something that Dae has worked on.
... How about we set a target for assigning issues?

Nigel: I'd like to treat this more like weekly sprints so please assign yourself issues on a
... week by week basis so that we can track the curve as the weeks go by and not block
... others from picking up issues because they're already assigned, if that is ok.

David_Ronca: That's fine, I'll pick that up with the team next week.

Nigel: Can anyone else let us know now about any issues they can pick up and work on
... over the next week?

Pierre: What about the TTML1 issues?

Nigel: They're in scope too because they generally apply to both TTML1 and TTML2.

Pierre: Here's a simple one:

tts:extent="auto" vs tts:extent="100% 100%"

Nigel: That's assigned to Glenn, and he said he is rewriting that text anyway.

Pierre: That was in November.

Glenn: On this particular one I don't actually agree with the proposed change. Auto is a
... proxy we often use to express a default without repeating the definition of the default
... everywhere that proxy is used. I don't think there's any technical reason not to use auto
... in place of 100% 100%. Also if we use auto then it's easier to change what that means in
... one place, rather than everywhere it is used.

Nigel: If that's your thought process it would be helpful to add it to the issue.

Glenn: Basically I consider this issue to be a request for early binding of the extent.

Nigel: In this case maybe the preferred choice is to close the issue without any change.

Glenn: The TTML1/TTML2 issue is an important one. In principle we should have resolved
... all the open TTML1 issues and incorporate those resolutions into TTML2 before PR,
... would anyone disagree with that?

Nigel: I think that's already agreed.

Pierre: Agreed.

Glenn: I just want to point out we don't have tracking issues for every TTML2 issue that has
... a TTML1 issue, so there is more work than is indicated by the currently open issues.

Nigel: How should we handle that, open tracking issues, or add the TTML1 issues to the set
... we are tracking for TTML2?

Glenn: Or we could open an umbrella issue for TTML2.

Nigel: That could simply consist of a list of TTML1 issue references.

Glenn: I think it would be useful to have that umbrella issue at least to begin with.

Nigel: Shall I create that umbrella issue?

Glenn: Thanks.

David_Ronca: I have to drop off now - thanks a lot guys.

Pierre: How about:

Step 10.4.4.2(6)(a) does not apply to textDecoration

Pierre: This is discussed and agreed, really narrow, has had no movement since London, so
... that would be a perfect candidate in my mind for anyone in the group to take on.

Glenn: As I already mentioned, if you would like to add yourself to an issue assigned to me,
... feel free to do that.

Nigel: can anyone take this on?

Glenn: We need to resolve this in TTML1 - coincidentally it is #219 in TTML1.
... This comes under the PR for TTML1.

Pierre: I'd like to broaden the set of folk working on stuff.
... I'd get to it eventually but I'm going to prioritise the HR comments.

Glenn: I'll get to it eventually as well.

<scribe> ACTION: nigel Create an umbrella issue for TTML1 issues in TTML2 [recorded in http://www.w3.org/2017/04/27-tt-minutes.html#action01]

<trackbot> Created ACTION-496 - Create an umbrella issue for ttml1 issues in ttml2 [on Nigel Megitt - due 2017-05-04].

Nigel: OK let's take that general approach - nobody is coming forward for this now but I
... guess some folks' ears are burning but they want to think about their workload and look
... at the open issues and see what they can take on.
... We'll come back to this again next week, and obviously anyone can assign themself to an
... issue in the meantime.
... The next thing to do is to review the existing open pull requests.

Clarify application of padding (#221)

Glenn: Andreas and I have gone back and forth on the utility of adding implementation detail.
... I agree that we could say a little more because it doesn't hurt to contextualise the subject
... with regards to the XSL-FO model. I'm not prepared to go all the way to the level of detail
... that Andreas originally proposed.
... Looking at today's comment, Andreas said that how padding is applied diverges from XSL-FO.
... I don't agree with that because, although XSL-FO does have some semantics regarding
... regions and page layout semantics, the TTML definition of region is entirely different.
... Maybe we need to point that out, in any case we are defining something different and
... saying how it maps to XSL-FO, in §9.3.3 Synchronic Document Construction.
... What it might be useful to do, as a subset of what Andreas proposed, is to add a note that
... clarifies that the extent of region maps to the allocation rectangle of the block area that
... is generated by the block container to which the TTML region element is mapped.
... See also my comments on https://github.com/w3c/ttml1/pull/233#issuecomment-297637021
... In earlier comments I think Pierre had asked the question of whether extent maps to
... padding rectangle or content rectangle, and I commented that it is neither, but to the
... allocation rectangle from which those other rectangles are derived. I'm prepared to add
... an additional comment with less detail than what Andreas asked for but says what I just
... said but does attempt to clarify that mapping.

Andreas: In response to the first point, I'm still of the opinion that on this one area we
... really diverge from XSL-FO and that makes it hard to explain how we relate to XSL-FO and
... also CSS. I was not referring to the region element in XSL-FO, but to the way block areas
... are handled. The way TTML does it, defining the allocation rectangle and then applying
... inset space has no correspondence in XSL-FO. You cannot define the width and height
... of an allocation rectangle in XSL-FO, which makes it hard to relate to and also tricky to
... implement using CSS models and concepts. We both expressed our points, but the most
... important thing is that users get the right understanding. I'm happy with any change
... that gives users the right understanding of how this works.

Nigel: Are you saying that Glenn's proposal would achieve that or not?

Andreas: As I mentioned, I would like input from other members of this Group too.
... If we can explain how it works clearly without referencing the conceptual model then
... I am happy with that, but I want to hear other opinions about it.

Glenn: I have an addendum to my opinion: another way to think about it is to posit the
... existence of a container that the block container is a child of, and then have the extent
... of the TTML region be assigned to the content rectangle of that posited outer shell
... container. That can be done conceptually without actually having to generate such an
... element in the flow object hierarchy. Or if one really wants to do that in XSL-FO there's
... an element called staticContent that could potentially be used for that purpose. A common
... use is for running headers and footers, except in XSL-FO the content is repeated on every
... page, though the generated ISD outputs could be considered to be pages in the XSL-FO
... sense, to make that leap of logic.

Andreas: I'm a bit worried that we make it even more complicated using a different solution.
... There is a discussed and agreed label, so I assume that members have read the original
... pull request and approved it. If we take on another edit then there must at least be some
... feedback from the group expressing some kind of preference.

Pierre: TTML1 has text directly relating to XSL-FO. Couldn't the clarification be put there?
... I understand that it might not be appropriate to put it far away from where it is defined.
... Surely there should be a place to put it assuming it is not false?

Glenn: I don't know if it is false or not - we could certainly put the detail note in §9.3.3
... where the allocation rectangle is defined. I think the current proposal is too detailed
... and application specific and I'm not prepared to accept it. Different implementations can
... do different things.

Andreas: I'm willing to accept the edited pull request from Glenn then. I read through it
... and also with the test cases provided by Pierre today it might be enough to see how it
... works. The trouble with XSL-FO is people might not be deeply into that, so its debatable
... how helpful it is. For me, if we use Glenn's edit and then possibly add some more text to
... clarify that extent corresponds to the allocation rectangle of the region then I'm fine with that.

Pierre: I'll file a separate issue because the same term "region area" is used for overflow and
... I'm fairly certain that we want any clipping to occur on the inset content area.

Andreas: There are different areas, but if we do not clarify exactly which one we mean then
... it is not clear which applies, so some additional wording would be helpful there.

Glenn: I assume that if clipping occurs then it is the content rectangle.

Pierre: I think that's what everyone assumes, so let's file an issue for that.

Glenn: I think I've heard a plan here to accept the pull request plus an additional note on
... §9.3.3 right under the bit about TTML regions mapping to block containers, in which I
... would say that it constrains the allocation rectangle. I can do that. First I will update the
... pull request with a new commit on that branch adding that note, and if the group accepts
... it then I'll go ahead and merge it. I'm asking that we pre-accept that so we don't need
... another round of review.

Pierre: The process is you'll submit the PR and then there's a 3 day review.

Glenn: I'm asking for a quick merge.

Pierre: I need the 3 days.

Andreas: I do too.

Nigel: Thanks for the constructive conversation everyone.

Andreas: I have to drop off - I just want to check about the agenda saying 60 minutes?

Nigel: The first line in the agenda should say 120 not 60 - that's an oversight on my part, apologies.

Andreas: OK. [leaves]

Nigel: Let's take a 5 minute break... [5 minutes elapses] ... and we're back

Glenn: I have one follow-up comment from before the break - I just want to remind us that
... strictly editorial non-substantive changes do not require the 3 day period according to
... the current process.

Pierre: I was not accusing you of being malicious by merging early, but for the point of
... efficiency it is a lot more efficient to leave a review period and deal with comments rather
... than open a new issue etc.

Glenn: My view is just the opposite about efficiency.

Nigel: Let's look at the next pull request:

Issue 0237 css2 reference

Glenn: I moved the reference to CSS2 to be in a Note and moved the CSS2 reference to the
... Other References because it is clearly no longer possibly normative.
... When it comes to merging this into TTML2 I need to re-review in case there are other
... places where CSS2 has come in as a normative reference.

Nigel: Yes, it's worth doing that review.
... Looks good to me.

Glenn: This will merge into the ED of TTML1 and then I will propose an equivalent pull request
... for TTML2.

Pierre: I will add a review approval too, to match the comment I made.

Nigel: With 2x LGTM you could probably merge this now but it would be fair in the process
... to wait until tomorrow Glenn.

Issue 0203 add examples of ja features part 2

Nigel: This has been open since March, what's going on...
... Okay we don't have Dae with us today, and the last status is that Richard Ishida was
... looking at it. I will prompt him.

Glenn: This contains some examples of some of the new Ruby functionality particularly
... Ruby overflow and Ruby Overhang and since I have not reviewed it I do not know if it
... correct. I will first of all review it for correctness.

nigel: I've added a comment to the pull request.

Revised tts:luminanceGain

Nigel: I haven't had chance to review this yet but it would be helpful to review and merge
... so I can merge the same fixes in to the other HDR pull request.

Glenn: It looks like that incorporates Nigel's comments.

Nigel: I see that, yes great, looks good.

Glenn: Can I go ahead and merge?

Nigel: If you've reviewed then it would be good to add that to the pull request.

Glenn: I've done that.

Nigel: I don't see why that can't be merged at this stage. Thank you.

Glenn: I'll do that after the call.

Nigel: Once you've done that then I'll update my follow-on pull request:

Issue #298 sRGB on HLG

Glenn: My only comment on that is that the newly added reference doesn't really match
... the format that we've used with the other ISO references, for example it includes the
... ISO reference within the title, whereas the others include only the name portion. The
... other is that you've been extremely specific in the way you have referenced the ISO number
... and the CIE number and the date, etc. and generally we have not added dates or tried
... to be overly specific on these references. Mike raised an issue on this recently that might
... bear on this point.

Nigel: That's:

reference versioning

Glenn: The first question is if we need both the ISO and the CIE references?

Nigel: I think so since the same document exists in both organisations.

Mike: Technically the CIE is a process document. They publish jointly with ISO.

Glenn: I would suggest using the ISO reference, rather than the CIE. Also you've used the
... key of CIE-XYZ. I like to keep those shorter.

Nigel: I'm happy to change the key to XYZ.

Glenn: If you do it that way you may be able to remove the CIE portion of the reference.
... Also you refer to a specific year on the ISO document, where we don't generally do that.
... For example we recently added CMAF without a year reference.

Mike: The first question is does W3C have a policy for what an unversioned reference means?
... If not then you need to put the version of the reference in.

Thierry: I don't think W3C defines what an unversioned reference means.

Glenn: Operationally speaking it has always been understood to mean "the latest" but it is
... not explicit. When Mike says that if there is no version then we must specify one. That
... has not been the practice in W3C or in TTML. For example we don't specify years in
... ISO specification references. If we create a new policy to reference versions then we are
... going to have to change a lot of references.

Mike: Certainly in TTML2, there's a lot of water under the bridge in TTML1. I don't follow
... your argument - we have a version of CSS2 for example that has been mentioned recently.
... My poster-child for this is a SMPTE document that references UNIX tar and someone
... blindly updated the year on the ANSI standard and in fact ANSI had entirely removed
... tar from that particular standard. You never know what you will get in future versions.

Glenn: One question is if there is a stable link to a document. For W3C specifications we
... generally use a dated link to the document on /TR, but HTML5 points to the unversioned
... "latest" link in /TR. One of the issue is that some of the linked URLs are not necessarily
... maintained by their organisations as stable URLs.

Mike: I think as a general rule no standards body (other than W3C or IETF) maintains
... stable links. In fact it is quite difficult to get older versions of things.

Glenn: Another thing I find interesting is that for IMSC1 we discussed dot-dot vs dot
... versions. Thierry mentioned that it is assumed that newer versions supersede older
... versions automatically. That surprised me. I've never thought that. That might explain
... why W3C has sometimes not put dated versions in, but that makes it a moving target
... as you have pointed out.

Mike: Yes, at some point you will get into trouble with interoperability.

Glenn: For TTML2 we need to review all of the references and decide if we want to augment
... them with version data.

Nigel: You could set a general rule of "the most recently published one at the time of
... spec publication" but that would be hard to manage.

Mike: That's impossible.

Pierre: Yes that's too difficult.
... The way to go is to use dated versions except where we specifically want to track changes,
... for example for registries.

Mike: That makes sense.

Glenn: Maybe the resolution for #293 is to go through all the references and check them out.
... That's not one that I assigned myself to. Maybe someone would like to do that.

Mike: If it is not the current version of the spec as it is today then I'm not sure how we go
... about resolving that. For example with CSS2 vs CSS2.1 we know there is a difference and
... there's a right answer. The thing that triggered it for me is documents I know about - I
... can certainly fix those. I don't know about the W3C references.

Glenn: I'm looking at the W3C references in TTML2 and it looks as though all of them point
... to a dated version, so that shouldn't need changing. I have always avoided the "latest" link.

Nigel: Can I assign this to you for those you can handle Mike?

Mike: Sure. For normative references especially we need to be specific. It may be as simple
... as putting the date in. So I might be able to do this even for the W3C references if the
... dates are already present.

Nigel: Ok I've changed the labels, added a comment and assigned that issue.
... For the pull request #299 Glenn please could you add those comments and I will
... process them?

Glenn: Okay.

Issue 0296 inline block

Nigel: We don't really have time to cover this today, I have added some review comments
... and asked a question.

TPAC 2017 planning.

Nigel: Note I have completed the survey for the group, with answers as described in the
... agenda - please let me know if you think any of those answers need to be changed.

HDR in PNG

Pierre: How do we proceed to publishing that Note?
... I have forwarded it to Chris Lilley and have not heard back so should we just put it up for
... official review on the reflector, asking for review, and then we can go ahead?

Nigel: yes, that seems like a good way forward.

Glenn: And the audience for review is our working group?

Pierre: Correct.

Nigel: If anyone (in or out of this group) has an interest feel free to point them to it.

Glenn: We don't have an obligation for review for the Note.

Pierre: I'd suggest starting a review clock for this.

Nigel: When would you close the review?

Pierre: Two weeks from today - if anyone asks for more time then we can adjust.
... That would be May 12th.

Nigel: Okay, I'll send out a request to the group.

Action-495?

<trackbot> Action-495 -- Thierry Michel to Update the ttwg homepage and publications pages for the new repos -- due 2017-04-20 -- OPEN

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/495

Thierry: I'll update those pages to reference the HDR in PNG document.

Nigel: I'd be very interested to know Chris Lilley's opinion too.

Thierry: I will ping him again.

IMSC

Nigel: I think the point to raise here is about CR exit criteria.

Pierre: Yes, I am also waiting for comments to come back. The baseline is only to test
... the added features. I don't have a lineGap implementation. It might be nice to have a
... vertical writing example too.
... I will ask Andreas about that.
... I don't expect a large test suite but it will be a challenge to generate the examples.

Nigel: I know we updated our gstreamer implementation to do lineGap but I do not know
... if it does vertical writing.
... We had a liaison response today, available at https://lists.w3.org/Archives/Member/member-tt/2017Apr/0004.html
... The sender requested member-only visibility.
... I should also have mentioned under TTML2 that there was some further TAG
... discussion, at:

Timed Text Markup Language 2 (TTML2)

Pierre: I might be able to point the commenter at IMSC.js for a practical example of the polyfill question.

Glenn: I would say that it is a subset, since practicality might be arguable. Not "the practical subset" but "a practical subset".

Nigel: I also want to acknowledge Pierre's message about the test suite - thank you for that.
... Thank you everyone, we are slightly over time today, apologies. [adjourns meeting]

s/Ok, the flip side of that is that is that if/If

Summary of Action Items

[NEW] ACTION: nigel Create an umbrella issue for TTML1 issues in TTML2 [recorded in http://www.w3.org/2017/04/27-tt-minutes.html#action01]
 

Summary of Resolutions

[End of minutes]

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